http://www.castlewales.com/mar_chld.htmlOn April 23, 1224, William Marshal married the sister of King Henry III, Eleanor. She was only nine at the time of this marriage, and it seems that King Henry III married her to Marshal to keep Marshal from marrying into either a Normandy family and increasing his ties to his brother Richard or into the de Brus family and strengthening his ties to Scotland. One has to wonder what William’s father would have thought of the marriage of his son to a child of King John. William Marshal senior had always been aware of the delicate balance of power between a feudal baron and his king as overlord. It is very probable that William senior would have strongly disapproved of his son marrying into the royal family because it would have severely limited his son’s ability to remain a baronial check against the possibility of royal abuse of law and power.